I could write a few chapters about headlight bezels...
a few things to remember -
GM made three different versions of headlight bezels before they were discontinued.
first GM production run that came as factory installed and available into the early 1990's were molded in GRAY ABS and then painted black or chromed. these bezels did not have the tab extensions on the inside at the corners. over time, these sagged in the middle between high and low beams.
below is a pic of the first GM version.
second production run from mid/late 1990s to about 2002 were molded in BLACK ABS. otherwise same as the first version.
below is a pic of the second GM version - molded in black
for the third GM version, production was moved to Canada. The Canadian produced bezels were molded in GRAY ABS and painted BLACK or Chromed as needed. Notice the Canada version has the tab extensions on the inside corners in an effort to stop the sag the previous versions suffered over time.
below is a pic of the third GM version - molded in gray with the tab extensions and painted black
It's important to remember for GM originals, at the corner of the marker lights, the bezel molding marks are ANGLED.
For the aftermarket headlight bezels...
there are two versions available - creations by two different companies.
Goodmark had a version made that is most like the first version by GM
Gilbert's g-body had one version made using a visually different extension tab on the inside as well as a different molding mark at the marker light to avoid copyright infringement.
because of post attachments limited to 10, there will be separate posts for each of these aftermarket versions containing the pics taken from internet listings.